This invention relates generally to a tensioning apparatus for a lashing strap, and more particularly to a lock for the tensioning apparatus.
The invention is particularly applicable to and will be described with specific reference to a tensioning apparatus which employs ratcheting mechanisms for tensioning and releasing the lashing strap. However, those skilled in the art will recognize that the invention may have broader applications and could be utilized in tensioning apparatuses that utilize crank mechanisms other than ratchets.
The following patents listed below are incorporated herein by reference and made a part hereof so that details related to the ratcheting mechanisms illustrated therein need not be repeated in detail in this patent:
1. U.S. Pat. No. 5,426,826 to Takimoto, issued Jun. 27, 1995, and entitled RATCHET BUCKLE ASSEMBLY;
2. U.S. Pat. No. 5,282,706 to Anthony, et al., issued Feb. 1, 1994, and entitled RETRACTABLE TIE-DOWN ASSEMBLY; and,
3. U.S. Pat. No. 5,271,606 to Kamper, issued Dec. 21, 1993, and entitled TENSIONING RATCHET FOR A LASHING STRAP.
The materials incorporated by reference, while included in this invention herein, do not, per se, form the present invention.
It is well known that in order to transport goods, equipment, and vehicles, it is necessary to secure these items with a plurality of tie-down straps. The number of tie-down straps required generally depends on the size and type of goods to be hauled by the vehicle.
In prior art tie-down assemblies, each tie-down strap usually has a hook at each end and some mechanism for adjusting the length of the strap that is disposed between the two ends. The adjusting mechanism is often a ratchet tightening device disposed between the ends of the strap. Conventional tie-down apparatuses generally include a tensioning apparatus of the type that includes a U-shaped frame having side walls with a rotatable spindle bridging the space between the side walls. One end of the lashing strap is fixed to the frame and the other lashing strap end is threaded onto the spindle. A tensioning handle with a pawl is pivotally mounted to the frame, and cooperates with a ratchet wheel affixed to the spindle. Movement of the handle in one direction results in incremental angular movement of the spindle by engagement of the handle pawl with ratchet wheel. A spring bias arrangement is provided for release of handle pawl engagement with the ratchet wheel. Such tensioning apparatuses serve as tensioning and tie-down devices for actual straps, with lashing straps constituting the preferred embodiment of the tensioning and tie-down means, which may also be in the form of steel cables. With lashing straps, goods to be transported are secured with the necessary lashing tension to retain their position on transporting means, for example, the beds of trucks or the rooftops of automobiles.
Typical operation of a tie-down assembly includes encircling the load to be secured, pulling the loose end of the lashing strap through a slot within the spindle as far as this is possible without resistance. Then the spindle is rotated by pivoting a tensioning handle back and forth. The tensioning handle drives an externally-toothed ratchet wheel of the ratchet device in the tensioning direction of the spindle (or winding shaft), so that the lashing strap is wound around the winding shaft which acts in the manner of a wind-up reel and is thus charged with an increasing lashing tension.
One of the drawbacks of the prior art tie-down assembly straps is the fact that the ratchet mechanism does not secure the handle to the frame. The result is that one or more of the tie-down straps could be unintentionally released or the tension otherwise sufficiently reduced such that the goods that were once secured may be released from the trailer or rooftop of an automobile.
The prior art has, however, recognized that the lashing strap must be locked to maintain strap tension, and discloses a tie-down assembly that includes a locking mechanism mounted to the frame tensioning apparatus such as shown in U.S. Pat. No. 5,282,706. The locking arrangement described in the prior art represents a second spring actuated member engaged with the ratcheting spindle to allow the spindle to rotate only in a take-up direction unless the spring bias is disabled. The spring actuated member that engages the ratcheting spindle in the prior art is subject to wear and vibration on a moving vehicle and conceivably, the spring force exerted on the member will eventually be insufficient to retain the ratcheting spool in a fixed position. This could result in undesirable slack in the tensioning strap. More importantly, the spring actuated member that engages the spindle does not positively lock the handle to the frame, and cannot prevent intentional release of the ratchet spool by an unauthorized person desiring to remove the secured goods (i.e. theft).
As previously discussed, the major drawback of the existing tensioning apparatuses is that in the final load securing stage, the tensioning handle remains unsecured. The lack of a positive securement mechanism for the tensioning handle enables inadvertent, accidental, and intentional or unintentional dislodgement. Dislodgement of the tensioning handle may result in releasing the tension of the lashing strap, thereby allowing the goods that are being transported to be released from the transport vehicle. Due to the fact that the lashing straps are typically used for securing goods on a moving vehicle, releasing of these goods from the vehicle may result in catastrophic accidents to vehicles and passengers following behind the subject vehicle. A principal drawback of the prior art device is that the tensioning apparatus with an unsecured tensioning handle allows unwanted tampering with the lashing strap and also allows potential theft of the secured goods.
It is therefore one of the major objects of the invention to provide a safe and lockable tensioning apparatus.
This object, along with other features of the invention, is achieved in a tie-down assembly for securing an article by a strap which includes a frame and a winding shaft journaled for rotation in the frame in a first payout direction and in an opposite second take-up direction whereby the length of the strap is shortened by being wound around the winding shaft in the take-up direction, and lengthened by being unwound from the winding shaft in a payout direction. The assembly additionally includes a ratchet wheel having ratchet teeth rotatable with the winding shaft, a handle associated with the winding shaft and movable from a second to a first position for rotating the winding shaft an incremental angle in the take-up direction while not rotating the winding shaft when moved from the first to the second position. The assembly further includes a spring biased handle pawl for engaging the ratchet teeth to allow rotation of the winding shaft by the handle in the take-up direction and prevent rotation in the payout direction. The spring biased handle pawl is capable of being moved out of engagement with the ratchet wheel to allow strap payout. In accordance with the invention, a key operated latch mechanism is provided for selectively locking the handle to the frame in the second position to, among other things, prevent theft of the goods secured by the tie-down assembly.
In accordance with another aspect of the invention, the key operated latch mechanism includes the handle center portion having a lock opening therein and a female latch member is connected to and straddles the frame side walls. The female latch member has a configured latch opening aligned with the lock opening when the handle is in the second position and a lock tumbler connected to said lock housing passes through the lock opening. A simple and effective lock is achieved by a rotatable male latch member attached to the base of the lock tumbler and configured to pass through the latch opening when the lock tumbler is in an unlocked condition and the handle is in the second position. In addition, the rotatable male latch member is unable to pass through the latch opening when the lock tumbler is in a locked condition.
In accordance with yet another aspect of the invention, the key operated latch mechanism includes the handle center portion having a lock opening therein and a female latch member having a top portion is connected to the frame. The female latch member is aligned with said lock opening so that the top portion of the female latch member extends through said lock opening when the handle is in the second position. Importantly, the top portion of the female latch member has a latch opening therethrough so that any conventional locking bolt adapted to extend through said latch opening can be provided for preventing movement of the handle relative to the frame.
In accordance with a more specific aspect of the invention, the locking bolt can simply be the U-shaped member of a conventional padlock.
In accordance with a still general aspect of the invention, a retractable tie-down assembly for securing an article by a strap is provided, which includes a frame to which one end of the strap is immovably secured. The assembly includes a winding shaft journaled for rotation in the frame and about which the strap is wound when the winding shaft is rotated in a take-up direction and unwound when the winding shaft is rotated in a payout direction. The tie-down assembly includes a handle pivotally mounted to and manually rotatable relative to the frame between first and second positions and an engagement mechanism for rotating the winding shaft in the retracting direction when the handle is moved from the second toward the first position while not rotating the winding shaft when the handle moves from the first toward the second position. A locking mechanism actuated by a key positively locks the handle to the frame when the handle is in the second position, whereby the lock is effective to lock the tie-down assembly irrespective of the particular type of engagement mechanism used in the tie-down assembly.
It is thus an object of the invention to provide a lockable tensioning apparatus.
It is another object of the invention to provide a safe tensioning apparatus.
Yet another object of the invention is to provide an economic, rugged and reliable locking mechanism for a tie-down ratchet assembly.
Still another object of the invention is to provide an inexpensive locking mechanism for a tensioning apparatus of the type described herein.
Still another object of the invention is to provide a lock mechanism which can be easily implemented or incorporated into existing tensioning apparatus.
These and other objects, features and advantages of the present invention will become apparent to those skilled in the art upon reading the detailed description of the invention as set forth below, taken together with the drawings which will be described in the next section.